Pump construction



March 24, 1942.

C. W. SHAW PUMP CONSTRUCTION Filed April 19, 1940 INVENTOK C/are/meyl\Yfian ATTORNEY.

atented I CONSTRUCTION Clarence W. Shaw, Grosse Yointc Woods, Mich,assignor to Eaton Manufacturing Company, Cleveland, Ohio, a corporationof Ohio Application April 19, 1940, Serial No. 330,521

1 Claim.

This invention relates to vehicle oil pumps in general, but moreparticularly concerns a pump gear or vaned wheel parts therein formoving the fluid supply, and which were not especially critical of theaccuracy of the inlet and outlet pump ports cast therein. More recently,a pump construction has found favor with automotive engineers and othersbecause of its general emciency compared to other known pumps and itsincreased efllciency at low speeds. Such a pump mechanism is based upontwo rotors or gears, one within and eccentric to the other, having toothdivisions, with contours on each out- 103-126) cored out of a boss castintegral with the engine block, the casting of the crescent shaped inletand outlet ports, which heretofore have been integral with andcountersunk in the rotor pocket, may not be cast within the limitsrequired to provide suitable inexpensive port shapes. This difilcultyhas been overcome in the present invention by casting a pump boss on theengine block, operating upon the boss to form the pump pocket thereinconcurrently with the machining operations performed upon the engineblock casting, and then introducing a separately cast 'or suitablyblanked steel porting plate insert into the pump pocket. Thereafter thepump rotors, shaft, and cover plate are added to complete the assembly.

Accordingly, the primary object of the present invention is theprovision of an engine block lined or generated by the tooth form of theother at regular angular motion, i. e. steady angular motion as the tworotors turn at speeds inversely proportional to the number of teeth toprovide rotor chambers separated by travelling tooth contacts forperforming pressure functions. A pump such as described above whileproviding improved results is rather critical in the accuracy requiredto form the porting arrangement therefor, and care must be exercised inthe machining operations performed upon the pump housing which isintegral with the inlet and outlet ports countersunk therein.

In the adaptation of this pump construction to automotive vehicles ithas been proposed to cast the pump housing integral with the enginecylinder block with a view, as aforementioned, to producing a moreeconomical unit. In this procedure the machining operations ordinarilyperformed upon a separate pump casting would be combined with and madeincidental to the operations performed upon the engine block casting.Intensive investigation has revealed that while the accurate portingarrangement required by this pump construction can be performed readilyupon a small separate pump casting it is not commercially feasible tomake the necessary port coring operations upon a casting the size of anengine cylinder block. That is to say, while the pump rotor pocket couldbe readily having a pump housing or pocket cast integral therewith andadapted to receive a separate pump porting plate insert in the pocket.Among the objects of the invention are the provision of a separatelyformed pump porting plate cast or blanked from steel including alocating pin thereon for suitably indexing and restraining the portplate in a pump pocket into which it may be introduced, and that is castintegral with an engine block; the provision in an engine blockconstruction as above described providing integral fluid passages to andfrom the pump pocket, including means for receiving the operating partsof the pump in associated relation with the engine mechanism, and covermeans, for retaining the pump mechanism in the engine block, readilyaccessible from the exterior of the block.

Further and other objects and advantages reside in the novel combinationand arrangement of parts to be hereinafter described when considered inconjunction with the drawing forming a part of this specification andpointed out with particularity in the appended claim.

In the drawing like reference characters denote corresponding partsthroughout the several views, and in which:

Fig. 1 is a vertical sectional view through a portionof an engine blockillustrating one form of this invention with a pump housing castintegral therewith and including a separate porting plate; and

Fig. 2 is an elevational view of the pump boss cast integral withtheblock of Fig. 1, showing the pump cover. removed to expose the rotorstherein; and

plate removed, revealing the countersunk pump pocket cored in the pumpboss; and

Fig. 4 is an elevational view of one form of separate porting plateinsert and locating pin for indexing the same when introduced into thepump pocket of Fig. 3; and

Fig. 5 is a vertical sectional view of the porting plate of Fig. 4,illustrating the ports therethrough, and taken substantially on the line5-5 thereof.

Now having reference to the drawing, and particularly Fig. 1, there isshown an engine block, generally designated l0, which has an oil sump orcrankcase secured therebelow. Projecting from a lower wall of the blockIII, adjacent the oil sump II, at any suitable angle is a boss |2 whichhas been cast integral with the engine block. Concurrently with theoperations performed upon the engine block casting the boss I2 is coredout to provide a countersunk pump pocket1|3 therein. From thecountersunk face of the pump pocket extend inwardly a pair of passagesl4 and I5, which may be holes readily drilled along with the otheroperations performed upon the block, and provide the inlet and outletfor oil to and from the pump, respectively. Communicating with the inletpassage H is another passage |6 drilled in the block and in the ceilingover the oil sump, from whence extends an oil pipe conduit securedthereto at its upper end by a fitting l8 and having its lower endextended deep down into the oil sump II with a filter screen l9 over thepipe end to strain the oil inducted thereinto. The outlet passage l5communicates with a rifle drilled oil gallery or is shown a separatelycast passage 20 which conducts lubricant under pressure to the severalparts-of the engine such as the camshaft bearings, crankshaft bearings,tappets, connecting rods, etc. (not shown).

In order to connect the pump mechanism with an operable part of theengine a third passage 2| also is drilled inwardly of the boss l2, fromthe face of the countersunk pocket |3 therein, into the hollow interiorof the block l0 and which serves as a journal for pump shaft 22, uponthe inner end of which is fixed a spiral gear 23 that meshes with acomplementary gear 25 on the camshaft 24 of the engine to be driventhereby. Upon the outer end of the pump shaft 22 a pump rotor 26 ispress-fitted, or, in this instance, as best shown in Fig. 2, is fixed bythe key 28. Surrounding the male pump rotor 26 is a female rotor 2'!which has'a running fit in the pocket l3.

It will be apparent that the female rotor 21 has one more internalcavity or tooth than the number of complementary shaped teeth on themale rotor 26 and are so dimensioned relative to each other that themale rotor which is mounted eccentric with respect to the female rotor,moves the same ahead of it progressively and continuously formingsuction and compression phases which are accurately timed with respectto the separate porting plate insert, about to be described, and thusprovides a continuous flow of lubricant under pressure when beingdriveryby the engine camshaft 24 through gear 23 on the pump shaft 22.The female and male rotors are provided with contours, such that theteeth of each in theory wipe or make continuous travelling contact overthose of the other during rotation. Since the pump frotors or operationthereof form no part of this invention the above provides a briefdescription of the actual pump operation suflicient for the purposes ofthis specification.

Figs. 3, 4, and 5 there 7 ported plate, generally designated 30, whichis arranged to be seated in the countersunk pocket l3 of the engineblock boss l2, overlying the inlet and outlet passages and |5 thereinand indexed relative thereto by the pin 3|, on the plate 30, in sertedin'the blind hole 32, in the countersunk pocket I3. The ports 33 and 34extended through the plate 30, and communicating with engine block theinlet and outlet passages l5 and I6 adjacent one face and the rotorparts 25 and Now having reference to 21 on the opposite face, aresubstantially crescent shaped and accurately cast, machined or blankedto secure the proper timed correlation between the rotor parts. Afurther circular through opening 35 in the ported plate 30 provides arunning fit for the pump shaft 22 threaded therethrough. Obviously, ofcourse, the shape of the ports 33 and 34 may vary according to therequirements desired in the finished pump to meet certain operatingconditions and the specific form shown is merely for purposes ofillustration. In some instances it may be possible to blank the portedplate 30 accurately out of steel or other suitable metal, andtheparticular type of separate ported plate used whether cast and machined,or blanked from sheet metal, is immaterial for the purposes of thisinvention.

In assembly, the porting plate 30 is seated in the countersunk pocketll, of the engine block boss I 2, and properly indexed with respect tothe eccentricity of the rotors and registering with the underlying inletand outlet passages l4 and H by the locating pin 3| and blind hole 32for receiving and stationarily retaining the same. The pump shaft 22with attached gear 23 is journalled in the drilled passage 2| of theblock and threaded through the opening 35 in the ported plate 30. Thedriving rotor 28 is then keyed or fixed on the end of the shaft andmeshed with driven rotor 21. Upon the outer face of the engine boss I2is an annular countersunk rubber-like gasket 31 over which in sealingrelation is a cover member 38 retained in place by any suitablefastening means 39- From the foregoing disclosures it will be apparentthere has been provided an engine block cast with an integral pump bossthereon which may be cored out and operated upon incidental to the usualmachining operations performed upon the block in a most economicalmanner, that is adapted to receive a novel separately cast orprefabricated pump Porting plate and other necessary pump parts, andwhich accomplishes among other things the objects and advantages of theinvention first enumerated. It is to be understood, however, thespecific form of the tration, as many other fonnal modifications andmechanical equivalents will present themselves in actual practice, whichwill come within the spirit and substance of the broad invention asdefined by the scope of the following claim.

What I claim is:

In an engine block construction, a pump boss cast integral therewith andadapted to be operated upon incidental to machining operations performedupon the block in reducing it to finished form-so as to provide acounterbore including inlet and outlet passages therein, a shaft boreterminating in said counterbore, a shaft housed in the shaft boreincluding a driv'e connection upon the inner end adapted to be meshedwith a driving means in the engine, an inlet conduit in registrationwith the inlet passage in aid counterbore, matched male and femaletoothed pump rotor parts adapted to be inserted in said counterbore withsaid male rotor secured to-said shaft for rotation of said rotors bysaid driving means in eccentric relation to each other thereby formingchambers which. expand and contract, and a separately fabricated portingplate adapted for insertion in said counterbore including means torestrain said porting plate in indexed relation to the eccentricitybetween said rotor parts and

